Conventional golf balls can be divided into two general classes: solid and wound. Solid golf balls include one-piece, two-piece (i.e., solid core and a cover), and multi-layer (i.e., solid core of one or more layers and/or a cover of one or more layers) golf balls. Wound golf balls typically include a solid, hollow, or fluid-filled center, surrounded by a tensioned elastomeric material, and a cover. Over the years, golf ball manufacturers have attempted, over the years, to manipulate the compositions of both the core and cover materials in order to satisfy the performance needs of skilled and recreational golfers. Golf ball performance can be judged by a wide spectrum of characteristics including resilience, durability, spin, and “feel” of golf balls. When formulating a composition for a golf ball, each element must be balanced to produce specific characteristics.
The combination of the solid core and ionomeric cover materials provide a ball that is durable and abrasion resistant. However, because these materials are rigid, solid balls can have a hard “feel” when struck with a club. Also, due to their construction, these balls tend to have a relatively lower spin rate and higher initial velocity, which can provide greater distance and increased accuracy off the tee but less control for greenside play.
Recently, manufacturers have investigated the use of alternative polymers, such as polyurethane, for use as golf ball covers. For example, U.S. Pat. No. 6,132,324, incorporated herein by reference, discloses a method of making a golf ball having a polyurethane cover. Polyurethanes have been recognized as useful materials for golf balls since about 1960. Polyurethane compositions are the product of a reaction between a curing agent and a polyurethane prepolymer, which is itself a product formed by a reaction between a polyol and an isocyanate.
The first commercially successful polyurethane covered golf ball was the Titleist Professional ball, first released in 1993. Subsequently, the Titleist Pro VI ball was introduced successfully in 2000 with a solid resilient polybutadiene core, a hard ionomer casing and a polyurethane cover. The Pro VI ball provided both professional and amateur players with long distance off of drivers and control for greenside play. However, further improvements in ball properties can be anticipated by varying the composition of the ionomer layer.
The present invention relates to a further attempt to provide a ball with equal or improved properties compared to the Pro VI achieved through the use of new compositions for use in golf ball layers.